Enzymatic esterification

ABSTRACT

Processes for preparing linear polyesters by reacting a dicarboxylic acid having from 2 to 10 carbon atoms, a polyol having from 2 to 15 carbon atoms, a low-boiling primary alcohol and a catalytic-effective amount of a lipase, wherein the reaction mixture is free of additional solvents; are described. The use of such linear polyesters in cosmetics is also described.

BACKGROUND OF THE INVENTION

Chemically, the esterification of dicarboxylic acids with polyhydricalcohols is very difficult to control and gives highly crosslinkedpolyesters at very high temperatures, i.e. beyond the melting points ofthe dicarboxylic acids. By contrast, the lipase-catalyzedtransesterification of dicarboxylic acid esters leads to the formationof linear polyesters under mild reaction conditions. By contrast, theesterification of the free dicarboxylic acids depends on the use of asolvent because the optimal reaction temperatures of the lipase arebelow the melting temperatures of the dicarboxylic acids.

Since the free dicarboxylic acids are more readily accessible on anindustrial scale than their esters, the problem addressed by the presentinvention was to provide a new process which would enable linearpolyesters to be obtained in quantitative yields and favorable reactiontimes from dicarboxylic acids and polyols under mild conditions withoutthe use of solvents.

BRIEF SUMMARY OF THE INVENTION

The present invention relates, in general, to processes for theproduction of linear polyesters from aliphatic, substituted aliphatic,aromatic and/or substituted aromatic dicarvoxylic acids and polyols inthe presence of small quantities of a low-boiling primary alcohol andlipase as catalyst but without the addition of solvent. The linearpolyesters can be used as thickeners and softeners in cosmeticpreparations.

The present invention also relates to the use of linear polyestersobtained by reaction of aliphatic, substituted aliphatic, aromaticand/or substituted aromatic dicarboxylic acids containing 2 to 10 carbonatoms and polyols containing 2 to 15 carbon atoms and at least twoprimary hydroxyl groups in the presence of small quantities of alow-boiling primary alcohol and lipase as catalyst without the additionof solvents as thickeners and softeners in cosmetic preparations.

It has surprisingly been found that linear polyesters can be obtainedfrom dicarboxylic acids and polyols for the first time without theaddition of solvents providing the reaction is carried out in thepresence of a low-boiling primary alcohol and lipase as catalyst. Theesterification is distinguished by mild reaction conditions, favorablereaction times and quantitative yields. The invention includes theobservation that advantageously water-soluble linear polyesters are alsoobtained where dicarboxylic acid mixtures containing hydroxydicarboxylicacids are used.

DETAILED DESCRIPTION OF THE INVENTION Dicarboxylic Acids

Aliphatic, substituted aliphatic, aromatic and/or substituted aromaticdicarboxylic acids containing 2 to 10, preferably 3 to 9 and morepreferably 4 to 6 carbon atoms are used for the production ofpolyesters. The aliphatic dicarboxylic acids used include, for example,oxalic acid, malonic acid, succinic acid and adipic acid, azelaic acid,dodecanedioic acid and brassylic acid while the aromatic dicarboxylicacids used include phthalic acid, isopththalic acid and terephthalicacid. The substituted dicarboxylic acids used include the aminodiacids,preferably glutamic acid, and hydroxydicarboxylic acids containing atleast two primary hydroxyl groups, preferably maleic acid, citric acid,glutaconic acid and glutaric acid and, more particularly, tartaric acid.Aliphatic unbranched dicarboxylic acids and hydroxydicarboxylic acidsare preferably used.

In addition, mixtures of dicarboxylic acids may be used, in which caseat least one dicarboxylic acid is a hydroxydicarboxylic acid containingat least two primary hydroxyl groups, preferably malic acid, citricacid, glutaconic acid and glutaric acid and, more particularly, tartaricacid. The molar ratio of dicarboxylic acid to hydroxydicarboxylic acidis 1:10 to 10:1, preferably 1:5 to 5:1 and more preferably 1:2 to 1:1.

Polyols

Polyols suitable for the purposes of the invention preferably contain 2to 15, more preferably 3 to 7 and more particularly 4 to 6 carbon atomsand at least 2, preferably at most 6 and more particularly 3 hydroxylgroups. The polyols may contain other functional groups, moreparticularly amino groups, or may be modified with nitrogen. Typicalexamples are

glycerol;

alkylene glycols such as, for example, ethylene glycol, diethyleneglycol, propylene glycol, butylene glycol, hexylene glycol andpolyethylene glycols with an average molecular weight of 100 to 1000dalton;

technical oligoglycerol mixtures with a degree of self-condensation of1.5 to 10 such as, for example, technical diglycerol mixtures with adiglycerol content of 40 to 50% by weight;

methylol compounds such as, in particular, trimethylol ethane,trimethylol propane, trimethylol butane, pentaerythritol anddipentaerythritol;

lower alkyl glucosides, particularly those containing 1 to 8 carbonatoms in the alkyl group, for example methyl and butyl glucoside;

sugar alcohols containing 5 to 12 carbon atoms, for example sorbitol ormannitol,

sugars containing 5 to 12 carbon atoms, for example glucose or sucrose;

amino sugars, for example glucamine;

dialcoholamines, such as diethanolamine or 2-aminopropane-1,3-diol.

Preferred alkylene glycols are propylene glycol, butylene glycol,hexylene glycol and polyethylene glycols with an average molecularweight of 100 to 1,000 dalton. Particularly suitable polyols areglycerol, sorbitol, sorbitan, trimethylol propane, pentaerythritol and2-aminopropane-1,3-diol. Oligomers thereof, for example dimers, trimers,tetramers, pentamers and/or hexamers, may also be used.

Low-boiling Primary Alcohols

Low-boiling primary alcohols suitable for the purposes of the inventionare alcohols with a boiling point below 100° C. Methanol, isopropanoland propanol and particularly ethanol are preferably used.

Lipases

Lipases derived from Candida cylindracea, Candida lipolytica, Candidarugosa, Candida antarctica B, Candida utilis, Chromobacterium viscosum,Geotrichum viscosum, Geotrichum candidum, Mucor javanicus, Mucor miehei,porcine pancreas, Pseudomonas species, Pseudomonas fluorescens,Pseudomonas sepacia, Rhizomucor meihei, Rhizopus arrhizus, Rhizopusdelemar, Rhizopus delemar, Rhizopus niveus, Rhizopus oryzae, Aspergillusniger, Penicillium roquefortii, Penicillum cambertii, Pseudomonasfluorescens or from an esterase of Bacillus sp., Bacillusthermoglucosidasius, Mucor miehei, horse liver, Saccharomycescerevisiae, pig liver are used as catalyst for the production of thelinear polyols according to the invention. The lipases may be usedindividually or in combination with one another. The lipases are used inquantities which effect adequate catalysis of the polyesterificationaccording to the invention and lead to a desired molecular weight of thelinear polyesters. Lipases derived from Mucor miehei and Aspergillusniger are preferably used. In particular, Novozym® 388 L (Rhizomucormiehei lipase, free), Lipozym® IM (Rhizomucor miehei lipase,immobilized), Novozym® 735 L (Candida antarctica B lipase, free),Novozym® 525 L (Candida antarctica B lipase, free) and/or Novozym® 435(Candida antarctica B lipase, immobilized), which are all products ofNono Nordisk, Denmark, are used. The lipases are preferably used inquantities of 0.01 to 15% by weight and more particularly in quantitiesof 1 to 10% by weight, based on the dicarboxylic acid.

Production Process

According to the invention, the linear polyols are obtained by reactionof mixtures of dicarboxylic acids containing a hydroxydicarboxylic acidwith polyols in the presence of small quantities of a low-boilingprimary alcohol and lipase as catalyst without the addition of solvents.The low-boiling alcohol released is preferably removed from the reactionmixture. The reaction is carried out at temperatures of preferably 50 to90° C. and more particularly 70° C. and under pressures of generally 0to 1013, preferably 0.01 to 500 and more preferably 10 to 250 mbar. Thereaction time is 8 hours to 4 days and preferably 24 to 48 hours. Toproduce the polyesters according to the invention, the dicarboxylicacids and polyols are used in a molar ratio of 2:1 to 0.5:1 andpreferably 1.2:1 to 0.8:1. The low-boiling primary alcohols are used ina 0.1 to 5 molar, preferably 0.2 to 2 molar and more preferably 0.3 to 1molar excess, based on the dicarboxylic acid. Polyesters with amolecular weight of 483 to 10,000 (as determined from GPC data andcalibration with polyethylene glycol) or 22,000 (as determined from GPCdata and calibration with polystyrene) may be obtained by this process.

Commercial Applications

The linear polyesters according to the invention may be used for theproduction of cosmetic preparations such as, for example, hair shampoos,hair lotions, foam baths, shower baths, creams, gels, lotions, alcoholicand aqueous/alcoholic solutions, emulsions, oils, wax/fat compositions,stick preparations, powders or emollients. These preparations maycontain mild surfactants, oil components, emulsifiers, superfattingagents, pearlizing waxes, consistency factors, thickeners, polymers,silicone compounds, fats, waxes, stabilizers, biogenic agents,deodorizing agents, anti-dandruff agents, film-formers, swelling agents,UV protection fractors, antioxidants, hydrotropes, preservatives, insectrepellents, self-tanning agents, solubilizers, perfume oils, dyes, germinhibitors and the like as further auxiliaries and additives.

Typical examples of suitable mild, i.e. dermatologically compatible,surfactants are fatty alcohol polyglycol ether sulfates, monoglyceridesulfates, mono- and/or dialkylsulfosuccinates, fatty acid isethionates,fatty acid sarcosinates, fatty acid taurides, fatty acid glutamates,ether carboxylic acids, alkyl oligoglucosides, fatty acid glucamides,alkyl amidobetaines and/or protein fatty acid condensates (preferablybased on wheat proteins).

Suitable oil components are, for example, Guerbet alcohols based onfatty alcohols containing 6 to 18 and preferably 8 to 10 carbon atoms,esters of linear C₆₋₂₂ fatty acids with linear C₆₋₂₂ fatty alcohols,esters of branched C₆₋₁₃ carboxylic acids with linear C₆₋₂₂ fattyalcohols, esters of linear C₆₋₂₂ fatty acids with branched alcohols,more particularly 2-ethyl hexanol, esters of hydroxycarboxylic acidswith linear or branched C₆₋₂₂ fatty alcohols, more particularly dioctylmalate, esters of linear and/or branched fatty acids with polyhydricalcohols (for example propylene glycol, dimer diol or trimer triol)and/or Guerbet alcohols, triglycerides based on C₆₋₁₀ fatty acids,liquid mono-/di-/triglyceride mixtures based on C₆₋₁₈ fatty acids,esters of C₆₋₂₂ fatty alcohols and/or Guerbet alcohols with aromaticcarboxylic acids, more particularly benzoic acid, esters of C₂₋₁₂dicarboxylic acids with linear or branched alcohols containing 1 to 22carbon atoms or polyols containing 2 to 10 carbon atoms and 2 to 6hydroxyl groups, vegetable oils, branched primary alcohols, substitutedcyclohexanes, linear and branched C₆₋₂₂ fatty alcohol carbonates,Guerbet carbonates, esters of benzoic acid with linear and/or branchedC₆₋₂₂ alcohols (for example Finsolv® TN), linear or branched,symmetrical or nonsymmetrical dialkyl ethers containing 6 to 22 carbonatoms per alkyl group, ring opening products of epoxidized fatty acidesters with polyols, silicone oils and/or aliphatic or naphthenichydrocarbons.

Suitable emulsifiers are, for example, nonionic surfactants from atleast one of the following groups:

(1) products of the addition of 2 to 30 moles of ethylene oxide and/or 0to 5 moles of propylene oxide onto linear fatty alcohols containing 8 to22 carbon atoms, onto fatty acids containing 12 to 22 carbon atoms andonto alkylphenols containing 8 to 15 carbon atoms in the alkyl group;

(2) C_(12/18) fatty acid monoesters and diesters of addition products of1 to 30 moles of ethylene oxide onto glycerol;

(3) glycerol monoesters and diesters and sorbitan monoesters anddiesters of saturated and unsaturated fatty acids containing 6 to 22carbon atoms and ethylene oxide adducts thereof;

(4) alkyl mono- and oligoglycosides containing 8 to 22 carbon atoms inthe alkyl group and ethoxylated analogs thereof;

(5) products of the addition of 15 to 60 moles of ethylene oxide ontocastor oil and/or hydrogenated castor oil;

(6) polyol esters and, in particular, polyglycerol esters such as, forexample, polyglycerol polyricinoleate, polyglycerolpoly-12-hydroxysterate or polyglyerol dimerate isostearate. Mixtures ofcompounds from several of these classes are also suitable;

(7) products of the addition of 2 to 15 moles of ethylene oxide ontocastor oil and/or hydrogenated castor oil;

(8) partial esters based on linear, branched, unsaturated or saturatedC_(6/22) fatty acids, ricinoleic acid and 12-hydroxystearic acid andglycerol, polyglycerol, pentaerythritol, dipentaerythritol, sugaralcohols (for example sorbitol), alkyl glucosides (for example methylglucoside, butyl glucoside, lauryl glucoside) and polyglucosides (forexample cellulose);

(9) mono-, di- and trialkyl phosphates and mono-, di- and/ortri-PEG-alkyl phosphates and salts thereof;

(10) wool wax alcohols;

(11) polysiloxane/polyalkyl polyether copolymers and correspondingderivatives;

(12) mixed esters of pentaerythritol, fatty acids, citric acid and fattyalcohol according to DE 11 65 574 PS and/or mixed esters of fatty acidscontaining 6 to 22 carbon atoms, methyl glucose and polyols, preferablyglycerol or polyglycerol;

(13) polyalkylene glycols and

(14) glycerol carbonate.

Products of the addition of ethylene oxide and/or propylene oxide ontofatty alcohols, fatty acids, alkylphenols, glycerol monoesters anddiesters and sorbitan monoesters and diesters of fatty acids or ontocastor oil are known commercially available products. They are homologmixtures of which the average degree of alkoxylation corresponds to theratio between the quantities of ethylene oxide and/or propylene oxideand substrate with which the addition reaction is carried out. C_(12/18)fatty acid monoesters and diesters of addition products of ethyleneoxide onto glycerol are known as refatting agents for cosmeticcompositions from DE 20 24 051 PS.

C_(8/18) alkyl mono- and oligoglycosides, their production and their useare known from the prior art. They are produced in particular byreacting glucose or oligosaccharides with primary alcohols containing 8to 18 carbon atoms. So far as the glycoside component is concerned, bothmonoglycosides where a cyclic sugar unit is attached to the fattyalcohol by a glycoside bond and oligomeric glycosides with a degree ofoligomerization of preferably up to about 8 are suitable. The degree ofoligomerization is a statistical mean value on which a homologdistribution typical of such technical products is based.

In addition, zwitterionic surfactants may be used as emulsifiers.Zwitterionic surfactants are surface-active compounds which contain atleast one quaternary ammonium group and at least one carboxylate and onesulfonate group in the molecule. Particularly suitable zwitterionicsurfactants are the so-called betaines, such as the N-alkyl-N,N-dimethylammonium glycinates, for example cocoalkyl dimethyl ammonium glycinate,N-acylaminopropyl-N,N-dimethyl ammonium glycinates, for examplecocoacylaminopropyl dimethyl ammonium glycinate, and2-alkyl3-carboxymethyl-3-hydroxyethyl imidazolines containing 8 to 18carbon atoms in the alkyl or acyl group and cocoacylaminoethylhydroxyethyl carboxymethyl glycinate. The fatty acid amide derivativeknown under the CTFA name of Cocoamidopropyl Betaine is particularlypreferred. Ampholytic surfactants are also suitable emulsifiers.Ampholytic surfactants are surface-active compounds which, in additionto a C_(8/18) alkyl or acyl group, contain at least one free amino groupand at least one —COOH—or —SO₃H— group in the molecule and which arecapable of forming inner salts. Examples of suitable ampholyticsurfactants are N-alkyl glycines, N-alkyl propionic acids,N-alkylaminobutyric acids, N-alkyliminodipropionic acids,N-hydroxyethyl-N-alkylamidopropyl glycines, N-alkyl taurines, N-alkylsarcosines, 2-alkylaminopropionic acids and alkylaminoacetic acidscontaining around 8 to 18 carbon atoms in the alkyl group. Particularlypreferred ampholytic surfactants are N-cocoalkylaminopropionate,cocoacylaminoethyl aminopropionate and C_(12/18) acyl sarcosine. Besidesampholytic emulsifiers, quaternary emulsifiers may also be used, thoseof the esterquat type, preferably methyl-quaternized difatty acidtriethanolamine ester salts, being particularly preferred.

Superfatting agents may be selected from such substances as, forexample, lanolin and lecithin and also polyethoxylated or acylatedlanolin and lecithin derivatives, polyol fatty acid esters,monoglycerides and fatty acid alkanolamides, the fatty acidalkanolamides also serving as foam stabilizers.

Suitable pearlizing waxes are, for example, alkylene glycol esters,especially ethylene glycol distearate; fatty acid alkanolamides,especially cocofatty acid diethanolamide; partial glycerides, especiallystearic acid monoglyceride; esters of polybasic, optionallyhydroxysubstituted carboxylic acids with fatty alcohols containing 6 to22 carbon atoms, especially long-chain esters of tartaric acid; fattycompounds, such as for example fatty alcohols, fatty ketones, fattyaldehydes, fatty ethers and fatty carbonates which contain in all atleast 24 carbon atoms, especially laurone and distearylether; fattyacids, such as stearic acid, hydroxystearic acid or behenic acid, ringopening products of olefin epoxides containing 12 to 22 carbon atomswith fatty alcohols containing 12 to 22 carbon atoms and/or polyolscontaining 2 to 15 carbon atoms and 2 to 10 hydroxyl groups and mixturesthereof.

The consistency factors mainly used are fatty alcohols or hydroxyfattyalcohols containing 12 to 22 and preferably 16 to 18 carbon atoms andalso partial glycerides, fatty acids or hydroxyfatty acids. Acombination of these substances with alkyl oligoglucosides and/or fattyacid N-methyl glucamides of the same chain length and/or polyglycerolpoly-12-hydroxystearates is preferably used. Suitable thickeners are,for example, polysaccharides, more especially xanthan gum, guar-guar,agar-agar, alginates and tyloses, carboxymethyl cellulose andhydroxyethyl cellulose, also relatively high molecular weightpolyethylene glycol monoesters and diesters of fatty acids,polyacrylates (for example Carbopols® [Goodrich] or Synthalens®[Sigma]), polyacrylamides, polyvinyl alcohol and polyvinyl pyrrolidone,surfactants such as, for example, ethoxylated fatty acid glycerides,esters of fatty acids with polyols, for example pentaerythritol ortrimethylol propane, narrow-range fatty alcohol ethoxylates or alkyloligoglucosides and electrolytes, such as sodium chloride and ammoniumchloride.

Suitable cationic polymers are, for example, cationic cellulosederivatives such as, for example, the quaternized hydroxyethyl celluloseobtainable from Amerchol under the name of Polymer JR 400° , cationicstarch, copolymers of diallyl ammonium salts and acrylamides,quaternized vinyl pyrrolidone/vinyl imidazole polymers such as, forexample, Luviquat® (BASF), condensation products of polyglycols andamines, quaternized collagen polypeptides such as, for example,Lauryidimonium Hydroxypropyl Hydrolyzed Collagen (Lamequat® L, GrünauGmbH), quaternized wheat polypeptides, polyethyleneimine, cationicsilicone polymers such as, for example, amodimethicone, copolymers ofadipic acid and dimethylaminohydroxypropyl diethylenetriamine(Cartaretine®, Sandoz AG), copolymers of acrylic acid with dimethyldiallyl ammonium chloride (Merquat® 550, Chemviron), polyaminopolyamidesas described, for example, in FR 2 252 840 A and crosslinkedwater-soluble polymers thereof, cationic chitin derivatives such as, forexample, quatemized chitosan, optionally in microcrystallinedistribution, condensation products of dihaloalkyls, for exampledibromobutane, with bis-dialkylamines, for examplebis-dimethylamino-1,3-propane, cationic guar gum such as, for example,Jaguar® CBS, Jaguar®C-17, Jaguar®C-16 of Celanese, USA, quaternizedammonium salt polymers such as, for example, Mirapol® A-15, Mirapol®AD-1, Mirapol® AZ-1 of Miranol, USA.

Suitable anionic, zwitterionic, amphoteric and nonionic polymers are,for example, vinyl acetate/crotonic acid copolymers, vinylpyrrolidone/vinyl acrylate copolymers, vinyl acetate/butylmaleate/isobornyl acrylate copolymers, methyl vinylether/maleicanhydride copolymers and esters thereof, uncrosslinked andpolyol-crosslinked polyacrylic acids, acrylamidopropyl trimethylammoniumchloride/acrylate copolymers, octylacrylamide/methylmethacrylate/tert.-butylaminoethyl methacrylate/2-hydroxypropylmethacrylate copolymers, polyvinyl pyrrolidone, vinyl pyrrolidone/vinylacetate copolymers, vinyl pyrrolidone/dimethylaminoethylmethacrylate/vinyl caprolactam terpolymers and optionally derivatizedcellulose ethers and silicones.

Suitable silicone compounds are, for example, dimethyl polysiloxanes,methylphenyl polysiloxanes, cyclic silicones and amino-, fatty acid-,alcohol-, polyether-, epoxy-, fluorine-, glycoside- and/oralkyl-modified silicone compounds which may be both liquid andresin-like at room temperature. In addition, a detailed review ofsuitable liquid silicones was published by Todd et al. in Cosm. Toil.91, 27 (1976).

Typical examples of fats are glycerides while suitable waxes are interalia beeswax, carnauba wax, candelilla wax, montan wax, paraffin wax,hydrogenated castor oils, fatty acid esters solid at room temperature ormicrowaxes, optionally in combination with hydrophilic waxes, forexample cetyl stearyl alcohol or partial glycerides. Metal salts offatty acids such as, for example, magnesium, aluminum and/or zincstearate or ricinoleate, may be used as stabilizers.

In the context of the invention, biogenic agents are, for example,tocopherol, tocopherol acetate, tocopherol palmitate, ascorbic acid,deoxyribonucleic acid, retinol, bisabolol, allantoin, phytantriol,panthenol, AHA acids, amino acids, ceramides, pseudoceramides, essentialoils, plant extracts and vitamin complexes.

Suitable deodorizers are, for example, antiperspirants, such as aluminumchlorhydrates. These antiperspirants are colorless hygroscopic crystalswhich readily deliquesce in air and which accumulate when aqueousaluminum chloride solutions are concentrated by evaporation. Aluminumchlorhydrate is used for the production of perspiration-inhibiting anddeodorizing compositions and probably acts by partially blocking thesweat glands through the precipitation of proteins and/orpolysaccharides [cf. J. Soc. Cosm. Chem. 24, 281 (1973)]. For example,an aluminum chlorhydrate which corresponds to the formula[Al₂(OH)₅Cl].2.5H₂O and which is particularly preferred for the purposesof the invention is commercially available under the name of Locron®from Hoechst AG of Frankfurt, FRG [cf. J. Pharm. Pharmcol. 26, 531(1975)]. Besides the chlorhydrates, aluminum hydroxylactates and acidicaluminum/zirconium salts may also be used. Other suitable deodorizersare esterase inhibitors, preferably trialkyl citrates, such as trimethylcitrate, tripropyl citrate, triisopropyl citrate, tributyl citrate and,in particular, triethyl citrate (Hydagen® CAT, Henkel KGaA, Düsseldorf,FRG). Esterase inhibitors inhibit enzyme activity and thus reduce odorformation. The free acid is probably released through the cleavage ofthe citric acid ester, reducing the pH value of the skin to such anextent that the enzymes are inhibited. Other esterase inhibitors aresterol sulfates or phosphates such as, for example, lanosterol,cholesterol, campesterol, stigmasterol and sitosterol sulfate orphosphate, dicarboxylic acids and esters thereof, for example glutaricacid, glutaric acid monoethyl ester, glutaric acid diethyl ester, adipicacid, adipic acid monoethyl ester, adipic acid diethyl ester, malonicacid and malonic acid diethyl ester, hydroxycarboxylic acids and estersthereof, for example citric acid, malic acid, tartaric acid or tartaricacid diethyl ester. Antibacterial agents which influence the germ floraand destroy or inhibit the growth of perspiration-decomposing bacteria,may also be present in stick products. Examples of such antibacterialagents are chitosan, phenoxyethanol and chlorhexidine gluconate.5-Chloro-2-(2,4-dichloro-phenoxy)-phenol, which is marketed under thename of Irgasan® by CibaGeigy of Basel, Switzerland, has also proved tobe particularly effective.

Suitable antidandruff agents are climbazol, octopirox and zincpyrithione. Standard film formers are, for example, chitosan,microcrystalline chitosan, quaternized chitosan, polyvinyl pyrrolidone,vinyl pyrrolidone/vinyl acetate copolymers, polymers of the acrylic acidseries, quaternary cellulose derivatives, collagen, hyaluronic acid andsalts thereof and similar compounds. Suitable swelling agents foraqueous phases are montmorillonites, clay minerals, Pemulen andalkyl-modified Carbopol types (Goodrich). Other suitable polymers andswelling agents can be found in R. Lochhead's review in Cosm. Toil. 108,95 (1993).

Examples of UV protection factors include organic substances (lightfilters) which are liquid or crystalline at room temperature and whichare capable of absorbing ultraviolet radiation and of releasing theenergy absorbed in the form of longer-wave radiation, for example heat.UV-B filters can be oil-soluble or water-soluble. The following areexamples of oil-soluble substances:

3-benzylidene camphor or 3-benzylidene norcamphor and derivativesthereof, for example 3-(4-methylbenzylidene)-camphor, as described in EP0693471 B1;

4-aminobenzoic acid derivatives, preferably 4-(dimethylamino)-benzoicacid-2-ethylhexyl ester, 4-(dimethylamino)-benzoic acid-2-octyl esterand 4-(dimethylamino)-benzoic acid amyl ester;

esters of cinnamic acid, preferably 4-methoxycinnamic acid-2-ethylhexylester, 4-methoxycinnamic acid propyl ester, 4-methoxycinnamic acidisoamyl ester, 2-cyano-3,3-phenylcinnamic acid-2-ethylhexyl ester(Octocrylene);

esters of salicylic acid, preferably salicylic acid-2-ethylhexyl ester,salicylic acid-4-isopropylbenzyl ester, salicylic acid homomenthylester;

derivatives of benzophenone, preferably2-hydroxy-4-methoxy-benzophenone,2-hydroxy-4-methoxy-4′-methylbenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone;

esters of benzalmalonic acid, preferably 4-methoxybenzalmalonic aciddi-2-ethylhexyl ester;

triazine derivatives such as, for example,2,4,6-trianilino-(p-carbo-2′-ethyl-1′-hexyloxy)-1,3,5-triazine and OctylTriazone, as described in EP0 818 450 A1;

propane-1,3-diones such as, for example,1-(4-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione;

ketotricyclo(5.2.1)decane derivatives, as described in EP 0 694 521 B1.

Suitable water-soluble substances are

2-phenylbenzimidazole-5-sulfonic acid and alkali metal, alkaline earthmetal, ammonium, alkylammonium, alkanolammonium and glucam-monium saltsthereof;

sulfonic acid derivatives of benzophenones, preferably2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and salts thereof;

sulfonic acid derivatives of 3-benzylidene camphor such as, for example,4-(2-oxo-3-bornylidenemethyl)-benzene sulfonic acid and2-methyl-5-(2-oxo-3-bornylidene)-sulfonic acid and salts thereof.

Typical UV-A filters are, in particular, derivatives of benzoyl methanesuch as, for exampleI-(4′-tert.butylphenyl)-3-(4′-methoxyphenyl)-propane-1,3-dione,4-tert-butyl4′-methoxydibenzoylmethane (Parsol 1789) or1-phenyl-3-(4′-isopropylphenyl)-propane-1,3-dione. The UV-A and UV-Bfilters may of course also be used in the form of mixtures. Besides thesoluble substances mentioned, insoluble pigments, i.e. finely dispersedmetal oxides or salts, may also be used for this purpose. Examples ofsuitable metal oxides are, in particular, zinc oxide and titaniumdioxide and also oxides of iron, zirconium, silicon, manganese, aluminumand cerium and mixtures thereof. Silicates (talcum), barium sulfate andzinc stearate may be used as salts. The oxides and salts are used in theform of the pigments for skin-care and skin-protecting emulsions anddecorative cosmetics. The particles should have an average diameter ofless than 100 nm, preferably from 5 to 50 nm and more preferably from 15to 30 nm. They may be spherical in shape although ellipsoidal particlesor other non-spherical particles may also be used. So-called micro- ornanopigments are preferably used in sun protection products. Micronizedzinc oxide is preferably used.

Other suitable UV filters can be found in P. Finkel's review inSÖFW-Journal 122, 543 (1996).

Besides the two above-mentioned groups of primary protection factors,secondary protection factors of the antioxidant type may also be used.Secondary sun protection factors of the antioxidant type interrupt thephotochemical reaction chain which is initiated when UV rays penetrateinto the skin. Typical examples of suitable antioxidants are amino acids(for example glycine, histidine, tyrosine, tryptophane) and derivativesthereof, imidazoles (for example urocanic acid) and derivatives thereof,peptides, such as D,L-carnosine, D-carnosine, L-camosine and derivativesthereof (for example anserine), carotinoids, carotenes (for exampleα-carotene, β-carotene, lycopene) and derivatives thereof, chlorogenicacid and derivatives thereof, liponic acid and derivatives thereof (forexample dihydroliponic acid), aurothioglucose, propylthiouracil andother thiols (for example thioredoxine, glutathione, cysteine, cystine,cystamine and glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl andlauryl, palmitoyl, oleyl, λ-linoleyl, cholesteryl and glyceryl estersthereof) and their salts, dilaurylthiodipropionate,distearylthiodipropionate, thiodipropionic acid and derivatives thereof(esters, ethers, peptides, lipids, nucleotides, nucleosides and salts)and sulfoximine compounds (for example butionine sulfoximines,homocysteine sulfoximine, butionine sulfones, penta-, hexa- andhepta-thionine sulfoximine) in very small compatible dosages (forexample pmole to μmole/kg), also (metal) chelators (for exampleα-hydroxyfatty acids, palmitic acid, phytic acid, lactoferrine),α-hydroxy acids (for example citric acid, lactic acid, malic acid),humic acid, bile acid, bile extracts, bilirubin, biliverdin, EDTA, EGTAand derivatives thereof, unsaturated fatty acids and derivatives thereof(for example γ-linolenic acid, linoleic acid, oleic acid), folic acidand derivatives thereof, ubiquinone and ubiquinol and derivativesthereof, vitamin C and derivatives thereof (for example ascorbylpalmitate, Mg ascorbyl phosphate, ascorbyl acetate), tocopherols andderivatives (for example vitamin E acetate), vitamin A and derivatives(vitamin A palmitate) and coniferyl benzoate of benzoin resin, rutinicacid and derivatives thereof, α-glycosyl rutin, ferulic acid,furfurylidene glucitol, carnosine, butyl hydroxytoluene, butylhydroxyanisole, nordihydroguaiac resin acid, nordihydroguaiaretic acid,trihydroxybutyrophenone, uric acid and derivatives thereof, mannose andderivatives thereof, Superoxid-Dismutase, zinc and derivatives thereof(for example ZnO, ZnSO₄), selenium and derivatives thereof (for exampleselenium methionine), stilbenes and derivatives thereof (for examplestilbene oxide, trans-stilbene oxide) and derivatives of these activesubstances suitable for the purposes of the invention (salts, esters,ethers, sugars, nucleotides, nucleosides, peptides and lipids).

Suitable preservatives are, for example, phenoxyethanol, formaldehydesolution, parabens, pentanediol or sorbic acid and the other classes ofcompounds listed in Appendix 6, Parts A and B of the Kosmetikverordnung(“Cosmetics Directive”). Suitable insect repellents areN,N-diethyl-m-toluamide, pentane-1,2-diol or Insect Repellent 3535. Asuitable self-tanning agent is dihydroxyacetone.

Suitable perfume oils are mixtures of natural and synthetic fragrances.Natural fragrances include the extracts of blossoms (lily, lavender,rose, jasmine, neroli, ylang-ylang), stems and leaves (geranium,patchouli, petitgrain), fruits (anise, coriander, caraway, juniper),fruit peel (bergamot, lemon, orange), roots (nutmeg, angelica, celery,cardamon, costus, iris, calmus), woods (pinewood, sandalwood, guaiacwood, cedarwood, rosewood), herbs and grasses (tarragon, lemon grass,sage, thyme), needles and branches (spruce, fir, pine, dwarf pine),resins and balsams (galbanum, elemi, benzoin, myrrh, olibanum,opoponax). Animal raw materials, for example civet and beaver, may alsobe used. Typical synthetic perfume compounds are products of the ester,ether, aldehyde, ketone, alcohol and hydrocarbon type. Examples ofperfume compounds of the ester type are benzyl acetate, phenoxyethylisobutyrate, p-tert.butyl cyclohexylacetate, linalyl acetate, dimethylbenzyl carbinyl acetate, phenyl ethyl acetate, linalyl benzoate, benzylformate, ethylmethyl phenyl glycinate, allyl cyclohexyl propionate,styrallyl propionate and benzyl salicylate. Ethers include, for example,benzyl ethyl ether while aldehydes include, for example, the linearalkanals containing 8 to 18 carbon atoms, citral, citronellal,citronellyloxyacetaldehyde, cyclamen aldehyde, hydroxycitronellal,lilial and bourgeonal. Examples of suitable ketones are the ionones,α-isomethylionone and methyl cedryl ketone. Suitable alcohols areanethol, citronellol, eugenol, isoeugenol, geraniol, linalool,phenylethyl alcohol and terpineol. The hydrocarbons mainly include theterpenes and balsams. However, it is preferred to use mixtures ofdifferent perfume compounds which, together, produce an agreeablefragrance. Other suitable perfume oils are essential oils of relativelylow volatility which are mostly used as aroma components. Examples aresage oil, camomile oil, clove oil, melissa oil, mint oil, cinnamon leafoil, lime-blossom oil, juniper berry oil, vetiver oil, olibanum oil,galbanum oil, labolanum oil and lavendin oil. The following arepreferably used either individually or in the form of mixtures: bergamotoil, dihydromyrcenol, lilial, lyral, citronellol, phenylethyl alcohol,α-hexylcinnamaldehyde, geraniol, benzyl acetone, cyclamen aldehyde,linalool, Boisambrene Forte, Ambroxan, indole, hedione, sandelice,citrus oil, mandarin oil, orange oil, allylamyl glycolate, cyclovertal,lavendin oil, clary oil, β-damascone, geranium oil bourbon, cyclohexylsalicylate, Vertofix Coeur, Iso-E-Super, Fixolide NP, evernyl, iraldeingamma, phenylacetic acid, geranyl acetate, benzyl acetate, rose oxide,romillat, irotyl and floramat.

Suitable dyes are any of the substances suitable and approved forcosmetic purposes as listed, for example, in the publication“Kosmetische Färbemittel” of the Farbstoffkommission der DeutschenForschungs-gemeinschaft, Verlag Chemie, Weinheim, 1984, pages 81 to 106.These dyes are normally used in concentrations of 0.001 to 0.1% byweight, based on the mixture as a whole.

Typical examples of germ inhibitors are preservatives which actspecifically against gram-positive bacteria such as, for example,2,4,4′-trichloro-2′-hydroxydiphenyl ether, chlorhexidine(1,6-di-(4-chlorophenyl-biguanido)-hexane) or TCC(3,4,4′-trichlorocarbanilide). Numerous perfumes and essential oils alsohave antimicrobial properties. Typical examples are the activesubstances eugenol, menthol and thymol in clove, mint and thyme oil. Aninteresting natural deodorant is the terpene alcohol farnesol(3,7,11-trimethyl-2,6,10-dodecatrien-1-ol) which is present in lindenblossom oil and which smells of lily-of-the-valley. Glycerol monolauratehas also been successfully used as a bacteriostatic agent. Thepercentage content of the additional germ-inhibiting agents is normallyabout 0.1 to 2% by weight, based on the solids component of thepreparations.

The total percentage content of auxiliaries and additives may be from 1to 50% by weight and is preferably from 5 to 40% by weight, based on theparticular composition. The compositions may be produced by standard hotor cold processes and are preferably produced by the phase inversiontemperature method.

EXAMPLES Example 1

4.6 g of ethanol (0.1 mole) and 9.2 g (0.1 mole) of glycerol were addedto 18.2 g (0.1 mole) of azelaic acid and the reaction was started with1.4 g (5% by weight) of Novozym® 435 (immobilized Candida antarctica Blipase from Novo Nordisk). After the reaction mixture had been stirredfor 4 hours at 75° C./1013 mbar, the pressure was reduced to 500 mbarand later to 50 mbar to continuously distill off the ethanol. After 24hours, the immobilized enzyme was removed by filtration. A yellowviscous liquid with a molecular weight (as determined from GPC data andcalibration with polystyrene) of ca. 1200 and an acid value of ca. 50was obtained in a yield of about 25 g.

Examples 2 and 3

The same reaction as in Example 1 was carried out with 6.0 g (0.1 mol)of isopropanol or propanol instead of ethanol, comparable results beingobtained.

Example 4

46.1 g (1 mole) of ethanol and 184.2 g (1 mole) of glycerol were addedto 150.1 g (1 mole) of L-(+)-tartaric acid and 188.2 g (1 mole) ofazelaic acid and the reaction was started with 26 g (5% by weight) ofNovozym® 435 (immobilized Candida antarctica B lipase from NovoNordisk). After the reaction mixture had been stirred for 6 hours at 80°C./1013 mbar, the pressure was slowly reduced to 200 mbar tocontinuously distill off the ethanol. The reaction time was 3 hours. Theimmobilized enzyme was then removed by filtration. A clear viscousliquid with a molecular weight (as determined from GPC data andcalibration with polystyrene) of ca. 1500 and an acid value of ca. 93was obtained in a yield of about 400 g. The product is soluble in water.

Example 5

46.1 g (1 mole) of ethanol and 92.1 g (1 mole) of glycerol were added to150.1 g (1 mole) of L-(+)-tartaric acid and the reaction was startedwith 12.1 g (5% by weight) of Novozymrn 435 (immobilized Candidaantarctica B lipase from Novo Nordisk). After the reaction mixture hadbeen stirred for 5 hours at 80° C./1013 mbar, the pressure was reducedin 24 hours to 200 mbar and, after another 24 hours, to 50 mbar tocontinuously distill off the ethanol. The immobilized enzyme was thenremoved by filtration. A viscous liquid with a molecular weight (asdetermined from GPC data and calibration with polystyrene) of ca. 1100and an acid value of ca. 122 was obtained in a yield of about 200 g.

What is claimed is:
 1. A process for preparing linear polyesters, saidprocess comprising: (a) providing a reaction mixture comprising adicarboxylic acid having from 2 to 10 carbon atoms, a polyol having from2 to 15 carbon atoms, a low-boiling primary alcohol and acatalytic-effective amount of a lipase, wherein the reaction mixture isfree of additional solvents; and (b) reacting the dicarboxylic acid andthe polyol.
 2. The process according to claim 1, wherein thedicarboxylic acid comprises a hydroxydicarboxylic acid having two ormore primary hydroxyl groups.
 3. The process according to claim 1,wherein the dicarboxylic acid comprises tartaric acid.
 4. The processaccording to claim 1, wherein the dicarboxylic acid comprises a mixtureof two or more dicarboxylic acids.
 5. The process according to claim 4,wherein the dicarboxylic acid comprises a hydroxydicarboxylic acidhaving two or more primary hydroxyl groups.
 6. The process according toclaim 4, wherein the dicarboxylic acid comprises tartaric acid.
 7. Theprocess according to claim 1, wherein the polyol comprises a componentselected from the group consisting of glycerol, alkylene glycols,technical oligoglycerol mixtures, methylol compounds, lower alkylglucosides, sugar alcohols, sugars, amino sugars, and mixtures thereof.8. The process according to claim 7, wherein the dicarboxylic acidcomprises a hydroxydicarboxylic acid having two or more primary hydroxylgroups.
 9. The process according to claim 7, wherein the dicarboxylicacid comprises tartaric acid.
 10. The process according to claim 7,wherein the dicarboxylic acid comprises a mixture of two or moredicarboxylic acids.
 11. The process according to claim 10, wherein thedicarboxylic acid comprises a hydroxydicarboxylic acid having two ormore primary hydroxyl groups.
 12. The process according to claim 1,wherein the lipase comprises a component selected from the groupconsisting of Candida antartica B and Rhizomucor miehei.
 13. The processaccording to claim 1, wherein the dicarboxylic acid and the polyol arereacted in a molar ratio of from 2:1 to 0.5:1.
 14. The process accordingto claim 1, wherein the dicarboxylic acid and the polyol are reacted ina molar ratio of from 1.2:1 to 0.8:
 1. 15. The process according toclaim 1, wherein the low-boiling primary alcohol is present in a molaramount of from 0.1 to 5, based on the molar amount of the dicarboxylicacid.
 16. The process according to claim 1, wherein the reaction of thedicarboxylic acid and the polyol is carried out at a pressure of from0.01 to 500 mbar.
 17. The process according to claim 1, wherein thereaction of the dicarboxylic acid and the polyol is carried out at apressure of from 10 to 250 mbar.
 18. A process for preparing linearpolyesters, said process comprising: (a) providing a reaction mixturecomprising; a dicarboxylic acid component comprising a mixture of ahydroxydicarboxylic acid having two or more primary hydroxyl groups andan additional dicarboxylic acid; a polyol component selected from thegroup consisting of glycerol, alkylene glycols, technical oligoglycerolmixtures, methylol compounds, lower alkyl glucosides, sugar alcohols,sugars, amino sugars, and mixtures thereof, a low-boiling primaryalcohol; and a catalytic-effective amount of a lipase selected from thegroup consisting of Candida antartica B and Rhizomucor miehei, whereinthe reaction mixture is free of additional solvents; and (b) reactingthe dicarboxylic acid and the polyol in a molar ratio of from 1.2:1 to0.8:1, and at a pressure of from 10 to 250 mbar.